I received an email showing someone unknown to me used my apple account to pay for a 99$ game. The link in the email didn't open to let me say I didn't authorize the purchase

If the only indication of the charges is from an email or text, be aware that it may be a phishing attempt to get you to log in to a site that appears to be Apple and divulge your password or credit card information. See: Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

and Identify legitimate emails from the App Store or iTunes Store - Apple Support

If the email was a scam as indicated above and if you used a link in the email and entered your password to sign in, your Apple ID is compromised. Change your password immediately. See: Change your Apple ID password - Apple Support

Also see: If you think your Apple ID has been compromised - Apple Support